The abrupt resignation of Sean O'Keefe will saddle NASA's next administrator with unfinished business: struggling to return grounded shuttles to space while keeping the nation on course for human expeditions to the moon and Mars. O'Keefe, 48, tendered his resignation Monday in a heartfelt, handwritten note to Bush.

A Soyuz capsule carrying a U.S.-Russian crew back to Earth following six months at the International Space Station hurtled through the Earth's atmosphere and landed safely and on target in Kazakhstan early Sunday.

Though cargo is piling up in the International Space Station and shuttles won't fly until after the new crew leaves, the astronauts on board are optimistic about their mission. This week, veteran crew members Gennady Padalka and Mike Fincke are teaching the ropes to new American Commander Leroy Chiao and Russia's Salizhan Sharipov.

China, a rising space power, provided journalists and local officials a rare look into its top-secret Jiuquan Satellite Launch Center on Wednesday, promoting the military-funded project as a lure for foreign investment. The center is a sprawling island of technological achievement in one of the country's poorest regions.

The International Space Station is getting along, Progress to Progress, without shuttles. Another of the unmanned Russian cargo ships blasted off from Kazakhstan overnight, carrying 2.8 tons of water, food and gear needed to keep the outpost staffed a few more months.

A spokesman for a Virginia company arranging aspiring U.S. space tourist Gregory Olsen's ride on a Russian spacecraft denied reports Wednesday that the trip was off because of Olsen's health problems. Earlier, the Interfax news agency cited an official at Russia's cosmonaut training center as saying that Olsen was rejected.

The U.S. scientist training to become the world's next space tourist won't get his wish after a Russian space committee vetoed his flight for health reasons, the Interfax news agency reported Wednesday.

A Russian Soyuz spacecraft carrying a U.S.-Russian-Dutch crew returned to Earth on Friday from the International Space Station, landing on target in the steppes of Kazakhstan. Expedition 8 crewmembers Michael Foale and Alexander Kaleri are returning to their home planet after spending six months aboard the ISS.

An American-Russian crew prepared Thursday to return to Earth in a Russian Soyuz spacecraft as they end their six-month mission on the International Space Station. The snug Soyuz TMA-3 capsule is scheduled to carry American astronaut Michael Foale and Russian cosmonaut Alexander Kaleri, home Friday.